function ex = cond_exp_logn(k, mu, sigma)
% Computes the expected value of a log normal RV
% the log of which has mean mu and standard dev. sigma
% conditional on being larger than a value k 

        ex = exp(mu + sigma^2/2)*(normcdf((log(k) - mu - sigma^2)/sigma))./...
        (normcdf((log(k) - mu)/sigma));
   

end